CODEWITHSUNDEEP
unixawk
ramaswamy
ramaswamy

Reputation: 121

How do I fetch this substring using awk?

I have a string let's say 

k=CHECK_${SOMETHING}_CUSTOM_executable.acs

Now I want to fetch only CUSTOM_executable from the above string. This is what I have tried so far in Unix

echo $k|awk -F '_' '{print $2}'

Can you explain how can i do this

Upvotes: 0

Views: 88

Answers (5)

TrueY
TrueY

Reputation: 7610

You do not need to use , it can be done in easily. I assume that $SOMETHING does not contains _ characters (also CUSTOM and executable part is just some text, they also not contains _). Then:

k=CHECK_${SOMETHING}_CUSTOM_executable.acs
l=${k#*_}; l=${l#*_}; l=${l%.*};

This cuts anything from the beginning to the 2nd _ char, and chomps off anything after the last . char. Result is put into the l env.var.

If $SOMETHING may contain _ then a little bit work has to be done (I assume the CUSTOM and executable part does not contain _):

k=CHECK_${SOMETHING}_CUSTOM_executable.acs
l=${k%_*}; l=${l%_*}; l=${k#${l}_*}; l=${l%.*};

This chomps off everything after the last but one _ character, the cuts the result off from the original string. The last statement chomps the extension off. The result is in l env.var.

Or it can be done using :

[[ $k =~ ([^_]+_[^_]+)\.[^.]+$ ]] && l=${BASH_REMATCH[1]}

This matches any string containing two words separated by _ and finished with .<extension>. The extension part is chomped off and result is in l env.var.

I hope this helps!

Upvotes: 0

αғsнιη
αғsнιη

Reputation: 2761

Try this simple :

awk -F[._] '{print $3"_"$4}' <<<"$k"

CUSTOM_executable

The -F[._] defines both dot and underline as field separator. Then awk prints the filed number 3 and 4 from $k as input.

If the k contains k='CHECK_${111_111}_CUSTOM_executable.acs', then use filed with numbers $4 and $5:

awk -F[._] '{print $4"_"$5}' <<<"$k"

CHECK_${111_111}_CUSTOM_executable.acs
| $1| |$2 | |$3| | $4 | |   $5   | |$6|

Upvotes: 0

sat
sat

Reputation: 14949

Suppose if SOMETHING variable is having 111_222_333 (or) 111_222_333_444,

Use this:

$ k=CHECK_${SOMETHING}_CUSTOM_executable.acs

$ echo $k | awk 'BEGIN{FS=OFS="_"}{ print $(NF-1),$NF }'

(Or)

 echo $k | awk -F_ '{ print $(NF-1), $NF }' OFS=_

Explanation :

NF - The number of fields in the current input record.

Upvotes: 0

Etan Reisner
Etan Reisner

Reputation: 80921

Assume the variable ${SOMETHING} has the value SOMETHING just for simplicity.

The following assignment, therefore,

k=CHECK_${SOMETHING}_CUSTOM_executable.acs

sets the value of k to CHECK_SOMETHING_CUSTOM_executable.acs.

When split into fields on _ by awk -F '_' (note the single quotes aren't necessary here).

You get the following fields:

$ echo "$k" | awk -F _ '{for (i=0; i<=NF; i++) {print i"="$i}}'
0=CHECK_SOMETHING_CUSTOM_executable.acs
1=CHECK
2=SOMETHING
3=CUSTOM
4=executable.acs

So to get the output you want simply use

echo "$k" | awk -F _ -v OFS=_ '{print $3,$4}'

Upvotes: 0

Gilles Qu&#233;not
Gilles Qu&#233;not

Reputation: 184975

Try this :

$ echo "$k"
CHECK_111_CUSTOM_executable.acs

code:

echo "$k" | awk 'BEGIN{FS=OFS="_"}{sub(/.acs/, "");print $3, $4}'

Upvotes: 1

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